Rescue workers late yesterday recovered the body of one of four men killed in an MX missile test silo during a flash fire Saturday that "went off like a sparkler," authorities said.

An engineer and two firefighters lowered into the silo at Arnold Engineering Development Center last night recovered the body, then re-entered the silo to search for the other dead men, said Bob Zimmerman, a spokesman for Pan American Services Inc., which provides security and food at Arnold.

Zimmerman said the body was identified as John P. Sipe, an employee of Sverdrup Technology Inc. of Tullahoma.

Two other men were injured in the fire, which broke out about 6 p.m. Saturday, engulfing the silo and consuming its contents.

Air Force Sgt. John Blackburn said a "large blaze" erupted in the 100-foot-wide vertical silo at Arnold Engineering Development Center, the nation's largest aerodynamics and propulsion testing center.

Blackburn said a spark or overheating during the cleanup operation may have touched off the fire.

"It was an instantaneous flash with tremendous heat . . . there wouldn't be any way they could have survived that flash," said Brig. Gen. Kenneth R. Johnson, commander of Arnold. "It went off like a sparkler with tremendous heat and energy."

Johnson said 50,000 pounds of solid rocket fuel dropped to the bottom of the 250-feet-deep cell Nov. 17 when a casing housing the fuel ruptured during testing of a stage 2 rocket motor.

The cause of that blast is under investigation.

Firemen used 3 million gallons of water to extinguish that blaze and then spent several days pumping water from the steel-reinforced, below-ground concrete silo so fuel recovery operations could begin.

Workmen began removing the fuel on Nov. 22, using manual slicers and drills.

"It's like slicing cheese," Johnson said. They had removed 20,000 pounds when something touched off the remainder Saturday.

The other three dead workers, employes of Aerojet Strategic Propulsion Co. of Sacramento, Calif., were identified by the firm as Dona J. Roy Jr., 57, a rocket test technician from Fair Oaks, Calif.; Murray L. Tauscher, 49, a senior test engineer of Roseville, Calif., and Arthur Totten, 48, a rocket test technician of Citrus Heights, Calif.

When the Saturday fire broke out, the three Aerojet employees were on the bottom of the silo cleaning up the fuel and the other victim was about 70 feet higher on an elevator, Johnson said.

A fireman and safety director employed by Pan Am World Services were overcome by fumes from the blaze.

The fire was extinguished at about 7:30 p.m. by firefighters in the center, Coffee County and nearby Manchester.

Luther Cross, a security officer, was in stable condition today at Harton Hospital; fireman David Harmon was treated and released.

The 41,000-acre site is about 60 miles southeast of Nashville. Tests are being conducted at the facility on the four-stage MX missile, the nuclear weapon President Reagan has named the "Peacekeeper."

Johnson said the accident will not delay the MX missile program. "We've already had five successful firings," he said.